DUGi

Role of spin state and ligand charge in coordination patterns in complexes of 2,6-diacetylpyridinebis(semioxamazide) with 3d-block metal ions: A density functional theory study

http://dugi.udg.edu/item/http:@@@@hdl.handle.net@@10256@@11439

We report here a systematic computational study on the effect of the spin state and ligand charge on coordination preferences for a number of 3d-block metal complexes with the 2,6-diacetylpyridinebis(semioxamazide) ligand and its mono- and dianionic analogues. Our calculations show excellent agreement for the geometries compared with the available X-ray structures and clarify some intriguing experimental observations. The absence of a nickel complex in seven-coordination is confirmed here, which is easily explained by inspection of the molecular orbitals that involve the central metal ion. Moreover, we find here that changes in the spin state lead to completely different coordination modes, in contrast to the usual situation that different spin states mainly result in changes in the metal-ligand bond lengths. Both effects result from different occupations of a combination of π- and σ-antibonding and nonbonding orbitals

The following organizations are thanked for financial support: the Ministerio de Ciencia e Innovacion (MICINN; Project CTQ2011-25086/BQU), the DIUE of the Generalitat de Catalunya (Project 2009SGR528, Xarxa de Referencia en Quimica Teorica i Computacional), and the Serbian Ministry of Education and Science (Grant 172035). Financial support from MICINN (Ministry of Science and Innovation, Spain) and the FEDER fund (European Fund for Regional Development) was provided by Grant UNGI08-4E-003

American Chemical Society (ACS)